Harrassment please help

I have an MBD company calling me every hour by the hour over 10 times a days for an amount I've paid. I have had an MTN data contract for close to three (3) years never had a problem with deductions from my bank account. They then start to have problem with deducting from my account and fail to let me know about that. They couldn't deduct for 3 months, they never called me, emailed me, called my other number that I use (mind you I have a dual sim phone so both my number work on this phone, if they called I would have a record and I don't). In that 3 months my service was not disconnected so I went on knowing they had deducted as the had done seamlessly for the the past 2 years. I then get my service disconnected and I call MTN, I'm told they want to hand me over for not paying. I explain that I wasn't told the first rude consultant said it's my fault because I need to ensure YOU GUYS take your money. 2 years, I need to scrutinize bank statements now after 2 years to make sure. I called again and a very helpful lady who told me the account hadn't had a 10 day lapse so I could just resolve this with MTN and that be that. I immediately paid the thousands and was done or so I thought. That's when the MBD crazy consultants started calling everyday all day without fail. 10 to 20 calls a day every single day!!! I kept telling them I didn't deal with them I paid mtn so they need to leave me alone but being as rude as they are they don't care. They want proof that I paid. Today I called MTN to ask for that proof. A consultant basically told I wasn't allowed to get proof.

So what do I do? MTN wont give me proof, mbd wont leave me alone until I give proof. These people are harassing me to the point where I am going to open a police case against them for harrassment. I can't live like this. I called your consultant about a month ago and she said they are talking ******* I have no debt with MTN.

PLEASE PLEASE HELP. If I paid you guys without them before that 10 day lapse why am i being harassed by them. I have was hospitalized but they dont care the harrassment doesn't end and i can't afford this stress. I really really really can't.